Question

10) Which of the following is always true for the oxidation numbers in an oxidation-reduction reaction? a) The value for the oxidation number for atoms of the element being oxidized must increase as we go from reactants to products b) The initial value for the oxidation number for atoms of the element being oxidized must be positive c) The final value for the oxidation number for atoms of the element being oxidized must be positive d) Both band c e) None of the above is always true 11) In the Arrhenius equation, the value for A, the pre-exponential factor, depends on a) the activation energy (the minimum energy needed to convert reactants into products) b) the collision frequency (number of collisions per unit volume and unit time) c) the orientation factor (the fraction of collisions that have an orientation favorable for reaction to occur) d) Both b and c e) Both a and b and 12) Which of the following is true of a catalyst? a) A catalyst is a substance b) A catalyst, when added to a reaction system, increases the rate at which the reaction occurs c) A catalyst is neither produced nor consumed as a reaction proceeds d) Both b and c e) Both a and b and c

Answer 1

10 Solution :

In a oxidation-reduction reaction or Redox reaction, oxidation is said to take place when the the oxidation state of the element in the reactant is increased in the products. It should increase irrespective of the fact the oxidation number is negative or positive in the reactants side.

So, according to the definition option a is correct.

Option b is incorrect because it has a condition of oxidation number of reactant being positive.

Option c is incorrect because it has a condition of oxidation number of product to be positive.

Option d is incorrect because option b and c are incorrect.

Option e is incorrect because option a is correct.

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